Apparatus for regulating and/or measuring the flow of fluids



y 1936- i G. WUNSCH ET AL 2,042,374

APPARATUS FOR REGULATING AND/OR MEASURING THE FLOW OF FLUIDS Filed Dec.51, 1955 A 2 Sheets-Sheet 1 Snow Mord y G. WUNSCH ET AL 2, 2,374

APPARATUS FOR REGULATING AND/OR MEASURING THE FLOW OF FLUIDS Filed Dec.31, 1935 2 Sheets-Sheet 2 Patented May 26, 1936 PATENT OFFICE.

APPARATUS FOR REGULATING AND/OR- MEASURING THE FLOW OF FLUIDS GuidoWiinsch, Berlin-Steglitz, Germany, and Alan James Douglas Hurnby,Ipswich, England,

assignors to Askaniatral Werkstatt Werke A. G. vormals Cen- Dessau undCarl Bamberg- Friedenau, a German company Application December 31, 1935,Serial No. 57,018 In Great Britain April 13, 1934 6 Claims.

This invention relates to apparatus for regulating and/or measuring theflow of fluids through mains or conduits and, among other objects, aimsto provide a relatively simple and reliable method of regulating'and/ormeasuring the weight of a fluid passing through a conduit whereinchanges in both the volume and the density or specific gravity of thefiuicl are governing factors. Another aim is to provide highlysensitive, rugged and reliable regulating apparatus for delivering aconstant weight of gas, such as air for supporting combustion, through aconduit, while .the density of the gas varies and, incidentally, formeasuring the flow in terms of standard conditions. Still another aim ofthe invention is to provide improved governing means of this type forcontrolling a variable delivery fan or pump in response to changes inthe volume and density of the fluid delivered thereby.

25 tus for practicing the method;

Fig. 2 is a similar diagrammatic view showing regulating apparatus only;and

Fig. 3 is a similar view showing flow measuring apparatus.

Referring particularly to the drawings, the apparatus shown in Fig. l isespecially adapted for controlling the delivery of air to a blastfurnace; although it has many other industrial applications. Herein, thesystem includes three jet pipe regulators of the well known Askaniatype, generally designated A, B, and C, acting in con junction with oneanother to maintain constant the weight of air flowing through the mainconduit, taking into account variations in air density. In thisinstance, a restriction or. fixed orifice plate In is provided in ablower outlet main or conduit I l to set up a differential pressurewhich is proportional to the square of the quantity or volume of airflowing therethrough, assuming that the ah; pressure and temperatureremain substantially constant. The difierential pressure is conveyed bytwo pipes l2 and I3 to a diaphragm chamber I4 and acts on opposite sidesof 9. diaphragm l5 of the regulator A which has a relay jet pipe Hi.This jet pipe I6 is supplied with air under pressure, conveniently fromthe main II and an air pressure is thereby set up in a conduit lldepending upon the extent to which the jet pipe registers with theorifice IS. The pres-, sure in the supplementary conduit Il'l is trans-Other aims and advantages of the invention mitted to a second diaphragml9' acting upon the relay jet pipe IS in opposition to the firstdiaphragm IE to counterbalance the jet pipe. The chamber above thisdiaphragm is vented to the atmosphere. -It therefore follows that theair pressure in the conduit l1 and on the second diaphragm I9 isdirectly proportional to the differential pressure set up at the orificeplate or restriction l0.

In this instance, a steam turbine is shown as driving a blower 2| whichis diagrammatically shown as being .a variable delivery pump and the airpressure in the conduit I1 is transmitted to the diaphragm 22 of thesecond regulator B which, in turn, controls the turbine speed by meansof a small control cylinder 23 having a piston 24 connected to theturbine governing gear G. The turbine governing gear is of conventionaldesign and is connected to the usual throttling valve V and the controlpiston modifies the action of the governor. The regulator B has an oiljet pipe 25, the movement of which in one direction results in anincrease and in the opposite direction in a decrease in the turbinespeed. I

In this example, a device of a well known type is associated with theregulator 13 to prevent the tendency of the governing gear to hunt dueto the inertia bf the turbine. If, for example, the air flow to thefurnace decreases so that the oil jet pipe 25.moves to the right andincreases the speed of the turbine by raising the pressure of oil in thepipe connection 26, then, due to the inertia of the turbine, the speedwill not respond instantly to movements of the regulator B and will nothave risen to its correct value when the regulator B has moved thegoverning gear G to its correct position. The regulator B will thereforetend to move the piston 24 in the control cylinder 23 and governinggearG still further and the blower 2| will ultimately be driven at anexcessive speed, causing the quantity of air to increase above normaland its pressure to be increased excessively. The regulator B would thenreduce the speed by increasing the oil pressure in the regulator pipeconnection 21, but here again, there will be a lagging between themovement of the regulator and the subsequent speed correction. Unlessprovision is made to prevent this,'the regulator would continue tooperate or hunt in this way.

In this instance, a stabilizer is installed in the pipe line 21 andincludes a cylinder 28 having a piston 29 which moves an adjustmentplunger 3!) for the jet pipe through a pivoted-lever 3|.

, tends to return to its neutral position under the The cylinder 29 isconnected in series with the control cylinder 23 and the movement of thepiston 29' therefore corresponds with all the movements of the controlcylinder piston 24. If the air volume decreases so that oil passes tothe control cylinder: 23 through the connection 26,

an equal quantity will return through the pipe 21 passing through thestabilizer, moving the piston 29 to the right and temporarilyreadjusting the regulator'for a smaller'quantity of air. The jet pipe 25therefore returns to its neutral position and remains in this position asufllcient time for the conditions to become stabilized, that is, forthe speed to change before anyfurther correction is made. If the airquantity rises above normal, the oil passes to the control cylinder 23through the pipe 21', shifting the piston 29 and temporarily readjustingthe regulator B for a smaller quantity of air. The action of this deviceis, therefore, to return the Jet pipe 25 to its neutral position andsuspend or. stop the action of the regulator when the piston 24 in'thecontrol cylinder 23 has moved through a definite portion of its stroke.This entirely eliminates the hunting which would otherwise occur. Thepiston 29 action of two springs 32, this being permitted by a valvedbypass 33, which allows oil to leak from one side of the piston to theother. Therefore, the final adjustment of the regulator is always thesame and the flow is maintained, irrespective of the positions of thecontrol piston and the control valve: There is no need to promain orconduit II is constant. In practice, however, the air density will varydue to the fluctuatingpressure .and temperature of the air from theblower 2| and also to variations in humidity.

[by means of two pipes 38 and 39 to a diaphragm To compensate forchanges in density, the third regulator C is connected to readjust theregulator A in'accorda'nce with-such variations. The airiiensity in themain conduit H is. measured by a small fan 34 of the positivedisplacement type. diagrammatically shown as being a constant deliverypump connected to a by-pass 35 having a restriction or orifice plate 39.This fan is shown as being driven by a three-phase motor 31. Thearrangement is such that thefan draws air from the main II and returnsit to the main through the restriction or orifice plate 36. The pressuredifferential across restriction 36 is always directly proportiona to thedensity or the air, owing to the constant volume delivery of the .fan34. This differential pressure is transmitted 49 in the regulator C.This diaphragm is balanced by a spring 4|, the force of which iscontrolled by the position of a piston 42 moved by oil delivered fromjet pipe 43 through conduits 44 and 45. For manual adjustment of theregulator, there is shown a ratio slider' cooperating with the usualpivoted counterlever 41. The purpose of this slider. is to match thespring characteristic of spring 4| to the diaphragm and thediflerentialpressure on 4ll.- J In this-instance, the

piston 42 has a piston rod 43 which carries a cam jet pipe i6 and apivoted counterlever 53.

' by a factor which is The density is measured as previously explained,75

49 acting on a plunger 59 which regulates the force of the spring 4|.The plunger is held in contact with the cam by a compression spring 5|.The cam 49 also operates a ratio slider 52 for the first regulator Aarranged between the This ratio slider is maintained in contact with thecam by means of a compression spring 54. Incias having ordinary rollerscontacting the'cam 49 to eliminate friction. Now, for an increase indentally, the plunger and ratio slider are shown differential pressureon the diaphragm due to I an-increase in density, the jet pipe 43 willmove to the left, while oil passes through the pipe 45 a and moves thepiston 42 upwardly, causing the cam 49 to compress the spring 4! untilits force just balances the pressure on the diaphragm. It

therefore follows that the ratio slider 52 is moved proportionally tothe pressure differential acting on diaphragm 40 and, therefore, inproportion to changes in the density of the air in the main I i. Inother words, there is a definite position of cam 49 for any density andthe stem carrying the cam :can be made to indicate and/or record densitytween the jet pipe l5 and the counter lever 53 is moved inwards. Thismeans that the action .of the diaphragm I5 is reduced and equilibriumwill be reestablished by a on diaphragm I9.

' The differential pressure impulse, which, in

lower pressure acting ordinary flow controls is applied directly ondiaphragm 22, is thus modified by means of regulator A and themodifiedimpulse represented by the pressure in i1, becomes a function of theflow modified by a factor which is a function of the density. By properdesign of the cam 49, it is evident to those skilled in the art that thepressure in pipe I1 can be. made directly to read weight units per timeunit.

Sincethe regulator A modifies the differential pressure obtained fromorifice l9' into an air pressure which is directly proportional to itand multiplies it by a factor which is changed by means of regulator Cas a definite function of the density measured by the differentialpressure across 36 the pressure obtained in conduit I! will alwaysrepresent the flow through. i I multiplied by a factor which is afunction of the density. -More particularly, it can be made to representfluid weight per. time unit, although the invention is by no meanslimited to that application. An ordinary pressure indicator or recorder55 can, therefore, be used to indicate and/or record the flow in weightunits pertime unit.

In -the operation of the device, the regulator A is readjusted by meansof the ratio slider 52 so that the pressure of air delivered to theregulator B is proportional to the weight of air delivered. Then, theregulator B controls the speed of the turbine 29 to maintain theweightof air delivered per unit of time,constant. When the density ofthe air changes, the differential pressure across the restriction III isno longer a correct reading of the weight and must be correctedproportional to the density.

by the fan 34 and the orifice 36 and the difi'erential pressure operatesthe third regulator C'which actuates the ratio slider 52, moving it adistance proportional to the density and thus giving the correctadjustment of the regulator A at all times. If it is not desired tomeasure the weight of air passing through the main I I and to obtain anindication or record of it, the first regulator A shown in Fig. 1 may beomitted and regulator B may be modified so that it is adjusted inproportion to variations in the air density in the same manner as is theregulator A. Such a modification is shown in Fig. 2, wherein theregulator C is identical in all of its details with the regulator C inFig. 1. The pipes 38' and 39 correspond with the pipes 38 and 39,respectively in Fig. 1 connected to the conduit on opposite sides of theorifice plate or restriction 36. The second regulator B is governed bythe difierential pressure on opposite sides of the orifice plate I!) inthe main conduit Il, being connected to said conduit by the pipes l2 andI3 which correspond with the pipes l2 and 13 connected to the regulatorA in Fig. 1. These pipes communicate with the opposite sides of adiaphragm 22' which actuates an oil jet pipe 25' and this oil jet pipedischarges into one or the other of the pipes 26 and 21' to actuate thepiston 24' which controls the governing gear. In this instance, astabilizer is also connected in series in line 21 with the controlcylinder 23' and the jet pipe 25 is counterbalanced by a plunger 30'which responds to the movement of the piston 29' of the stabilizer in amanner similar to that described in connection with Fig. 1. However, thejet pipe relay is readjusted in proportion to changes in density by theaction of the regulator C which operates a ratio slider 52' between thejet pipe 25' and a pivoted counterlever 53' in the same manner as shownin Fig. 1 in connection with the regulator A. Thus, the essentialfeatures of regulators A and B in Fig. 1, insofar as they apply to thecontrol of the turbine governor, have been combined in the regulator B.

It is also obvious that a simplified arrangement of the apparatus may beemployed for n'ieasur ing the quantity of air in terms of standardconditions passing through the main ll. Such an arrangement is shown inFig. 3 wherein two of the regulators corresponding exactly with theregulators A and C in Fig. 1 are employed. In this case, the regulator Bfor controlling the operation of the governing gear G is omitted and theair conduit I1" is connected to the indicator or recording instrument55", the pipe leading to the regulator B being also omitted.

It will be understood that the modifications or alternative embodimentsof the mechanism shown in Figs. 2 and 3 are sub-combinations of themechanism illustrated and explained in connection with Fig. 1, eachinvolving omission of 'certain parts and their functions.'

Reverting to the illustrated apparatus in Fig. 1, it will be understoodthat other means for constantly measuring the, density of the air in themain ll may be employed. Also, different forms of regulators may besubstituted for the regulators A, B and C. Furthermore, it will beunderstood that the regulator B shown as being connected to control thespeed of the turbine 20 which operates the air blower, may be employedto control the supply of fluid to conduit II in many other ways wellknown to those skilled in the art. The apparatus may also be used toMoreover, it is not indispensable that all parts ofthe separatelydisclosed apparatus shall be used conjointly, but they are capable ofembodiment in various combinations and sub-combinations.

What is claimed is:

1. In apparatus of the character described, a gas conduit having arestriction; a primary regulator having a member connected to beoperated by the differential pressure on opposite sides of saidrestriction; a relay member in the regulator controlled by said firstnamed member; a constant-speed, positive displacement pump having itsintake connected to said conduit and having a restriction in its outletto create a differential pressure impulse on opposite sides of therestriction which is proportional to the density of the gas in theconduit; a second regulator relay connected to be operated by saidimpulse; means connecting said second regulator to effect a compensatingadjustment of the said relay member in the primary regulator accordingto said changes in density; and means connecting said first namedregulator relay to control the rate of delivery of gas through saidconduit and maintain the weight flow substantially constant.

2. Apparatus for controlling the quantity of a gas passing through aconduit comprising. in

combination, a regulator connected to be operated in response to adifferential pressure propor- ,tional to the flow in said conduit; meansfor delivring a constant volume of the gas per time unit from theconduit through a restriction to create a differential pressureproportional to the density of the gas;- another regulator connected tobe operated in response to changes in the differential pressure onopposite sides of said reing a constant volume of the gas'per time unitfrom the conduit through a restriction to create a differential pressurealways proportional to the density of the gas; an auxiliary pressurerelay connected to be operated by said second named differentialpressure; a ratio adjusting device in said main pressure relay modifyingthe action of the first named difl'erential pressure thereon andconnected to be operated by said auxiliary pressure relay to create afluid pressure proportional to the weight flow; and a controlling relayoperated by the last named fluid pressure and connected to govern thespeed of said pump.

4. Apparatus for controlling the quantity of gas passing through aconduit comprising, in combination, a pump connected to deliver gas tothe conduit; a main pressure relay connected to connected to be operatedby said se'co nd named -difierential pressure; a ratio adjusting' devicein said main pressure relay modifying the action of to the weight flow;controlling means operated by the last named fluid pressure andconnected to govern the speed of said pump; and a stabilizing deviceassociated with said controlling means to prevent hunting of thegoverning means.

5. In combination with a gas delivering conduit having a restriction, aregulator connected to be operated by the differential pressure onopposite sides of said restriction and adapted to deliver a controllingimpulse which is proportional to said differential pressure; means fordelivering a constant volume of the gas per time unit from the conduitthrough a restriction to create a differential pressure proportional tothe density of the gas; a relay connected to be operated by said secondnamed differential pressure; a ratio adjusting device for said regulatormoditying the action of the first named differential pressure thereonand connected to be operated by said relay whereby said controllingimpulse is proportional to the weight flow of the gas per 1.

- pressure proportional to the rate of flow, means for delivering aconstant volume of gas per time unit from the conduit through arestriction to create a second difierential pressure proportional to thedensity of the gas; a regulator connected to be operated by said firstnamed diiferential pressure for creating a controlling impulse which isproportional thereto; and means responsive to the second diiferentialpressure connected to multiply the controlling impulse by a factor whichis always proportional to the density of the gas, whereby said controlimpulse is always proportional to the weight flow of the gas per-timeunit through the conduit.

' GUIDO WU'NSCH.

ALAN JAMES DOUGLAS HUMBY.

